In Vitro Evaluation of Changes in Hair Fibers Subjected to Oxidation-Reductive Straighteners Associated with Dyeing

This study evaluated the effects of ammonium thioglycolate and amino methylpropanol alkaline straighteners followed by permanent dyeing on hair fibers. Using techniques like FTIR, DSC, SEM, confocal and fluorescence microscopy, and others, the research found that both straightening and dyeing caused changes to the hair cuticle and cortex. Specifically, there was oxidation of surface bands and denaturation of alpha-keratin chains in the cortex. The study highlights the physical and chemical changes in hair fibers due to these cosmetic procedures, emphasizing the importance of understanding these effects for maintaining healthy hair.